JPS60153130A - Dry etching device for aluminum - Google Patents

Abstract

PURPOSE:To improve etching reliability by exhausting a residual etching gas after etching rapidly to prevent an aluminum film from being etched by the gas. CONSTITUTION:The anode 11a on the upper wall of a container 11 and a cathode 13 function as parallel flat electrodes. Then a valve 16 is arranged right before the place where a gas introducing pipe 17 is connected to the container 11 and it opens and closes synchronizing with a high-frequency power source 15. Also, a gas exhaust pipe 19 is connected to an exhaust vent 11c and the air in the container 11 is exhausted by a vacuum pump. At completion of etching, the valve 16 is closed and the etching gas in the gas introducing pipe 17 does not flow into the container 11. Accordingly, the gas in the container 11 can be exhausted rapidly and etching of a sample 13 made of aluminum and etc. by the residual etching gas is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an aluminum dry etching apparatus, and more particularly to a dry etching apparatus that improves uniformity.

[Technical Background of the Invention and Problems Therewith] In recent years, integrated circuits have been increasingly miniaturized, and recently, ultrafine elements with a minimum dimension of 1 to 2 [μII] have even been prototyped. For such microfabrication, a reactive gas such as CF4 is usually introduced into an evacuated container with parallel plate electrodes, and a glow discharge is generated by applying high-frequency power to the electrode (cathode) on which the sample is placed. The so-called reactive ion etching method (RI E : Reactive I on
E tcl+ i ng ) is used. However, this RIE method uses a glow discharge with a relatively low sludge dissociation effect, so for example, the 1-dipping rate of SiO2 using CF4+1-42 gas is at most 300~5
00 [contains], and it takes more than 30 minutes to etch 8102 with a film thickness of 1 [μm], making it difficult to mass-produce! It was hurtful and inconvenient.

Furthermore, when etching an aluminum film, the etching uniformity was poor and impractical.

On the other hand, as a solution to the problem of mass production, the present inventors have proposed a dry etching device in which magnetic field generating means made of a permanent magnet is provided under the cathode to which high-frequency power is applied, and high-speed etching is possible using magnetron discharge. It has been developed and introduced into the manufacturing process. However, even in this type of device, the uniformity of the aluminum film is still poor, and its introduction into the manufacturing process is currently delayed. One of the reasons for this is that the inventors
The experiment revealed the following.

FIG. 1 is a schematic configuration diagram showing a conventional dry etching apparatus. A vacuum container 1 includes a cathode 3 on which a sample 2 is placed and to which high-frequency power is applied, and a gas introduction pipe 4 for introducing the etching depth. and a gas exhaust pipe 5 for discharging these gases evenly to the sample. Using this equipment, high frequency power 850 [W], etching pressure 0.1 [Torr], etching gas BCfs:
The aluminum film was etched for 30 seconds under the conditions of 30 (SCCM>+CJ12: 50 (SCCM)), and the time from the end of etching, that is, from turning off the high frequency power to exhausting the etching gas, was 10 seconds.

The etching time was changed to 30 seconds and 60 seconds, and the sealing of the can was measured.

As a result, as shown in Figure 2, even though the etching time is constant, the etching depth near the gas inlet becomes deeper as the time until the nitching gas is exhausted becomes longer. It became clear. Further, as a result of observing the etching shape near the gas inlet using SEM, it was found that a large undercut had occurred.

This indicates that aluminum can also be etched by raw CJ12 after the surface alumina layer is removed, as is commonly reported, and the aluminum film can be etched with good uniformity and without undercuts. 1 indicates that it is necessary to remove the etching gas as quickly as possible after connitting (after turning off the high frequency power).

[Purpose of the Invention] The object of the present invention is to provide an aluminum dry etching apparatus which can cover an aluminum film with good uniformity and without causing undercuts, and which improves etching reliability. be.

[Summary of the Invention] The gist of the present invention is to quickly exhaust residual etching gas after etching to prevent the aluminum film from being etched by the residual etching gas.

That is, the present invention provides a tri-etching Hffi for etching aluminum, which includes an etching container;
A means for applying high frequency power between these electrodes; a gas introduction pipe connected to the container for introducing aluminum etching scum into the container; An opening/closing valve is provided at or near a position immediately before the gas introduction pipe comes into contact with the container, and opens and closes the gas flow path of the introduction pipe, and a first gas exhaust means is provided to exhaust the inside of the container, and the etching is completed. By closing the opening/closing valve at the same time, the etching gas remaining in the container after etching is completely vented. Note that, as a means for activating the double tincture gas, a light irradiator 48 may be used instead of the parallel plate electrodes disposed in the container and the means for applying high frequency power between these electrodes.

In addition to the above configuration, the present invention provides a second 7j gas means for exhausting and covering the inside of the gas introduction pipe between the on-off valve and the container, so that the residual etching residue can be exhausted more quickly. .

[Effects of the Invention] According to the present invention, since the opening/closing valve is provided immediately before the etching container, the amount of etching gas flowing into the container after etching can be extremely reduced. Therefore, after etching is completed, the etching gas remaining in the container can be quickly exhausted, and the uniformity of aluminum etching can be improved. Furthermore, undercut 1
- problems are eliminated, and highly reliable dry etching becomes possible. In addition, a second exhaust means is provided! In this case, the remaining etching gas after etching can be exhausted more quickly, and the reliability of etching can be further improved. 1 is a schematic configuration diagram showing a dry etching apparatus according to an embodiment. In the figure, 1" is an etching container, and this container No. 11 has a flat cathode 12 attached to close the bottom opening. , also constitutes a hermetically sealed etching. Container 11 is grounded and sample 1
High frequency power is applied from a high frequency power source 15 via a matching circuit 14 to the cathode 12 on which 3 is placed. Then, the upper wall (g4 pole) 11a of the container 11 and the cathode 13 act as a single parallel plate power recovery layer.

On the other hand, a scrap inlet 11b for introducing etching gas into the container 11 is provided on the upper wall 11a of the container 11.
A gas introduction pipe 17 is connected to this introduction port 111) via an electromagnetic opening/closing knob 1G.

That is, the valve 16 is provided just before the gas introduction pipe 17 is connected to the container 11 . The valve 16 is opened and closed in synchronization with the high frequency power source 15 by the operation of the switch circuit 18. That is, the closing operation is performed at the same time as the high frequency power supply 15 is turned off. Further, a gas exhaust port 11C is provided at the bottom of the container 11 for exhausting the etching gas in the container 11.
A gas exhaust pipe 19 is connected to 11C. Then, the inside of the container 11 is evacuated via a nozzle exhaust pipe 19 by a vacuum pump or the like (not shown).

Note that 21 in FIG. 3 is a water-cooled tube for cooling the cathode 12, and this water-cooled tube 1 is used as an electrode lead. Further, 22 indicates an insulator.

With this configuration, valve 1 is closed when etching is completed.
6 is closed, the etching gas in the gas introduction pipe 17 will not flow into the container 11 through the etching pipe 711. Therefore, the inside of the container 11 can be quickly evacuated, and the etching of the sample 13 such as aluminum due to the residual etching gas can be minimized. Therefore, it is possible to improve the uniformity of threading of aluminum.

FIG. 4 shows etching conditions similar to those described above using the above-mentioned apparatus, ie, high frequency power of 850 [W].

Etching pressure 0.1 [Torr], etching gas BCJ13: 30 (SCCM) + CJ12:
FIG. 5 is a characteristic diagram showing the etching distribution when aluminum is left in the container 11 for 60 seconds after being etched under the condition of 50 (SCCM). As you can see from this figure,
No phenomena such as abnormally deep etching near the gas inlet 11b were observed, and good etching uniformity was obtained. Further, as a result of observing the etching shape near the gas inlet 111) by SEM, almost no undercut was observed.

FIG. 5 is a diagram showing the main part configuration of another embodiment.

Note that the same parts as in FIG. 3 are given the same reference numerals, and detailed explanation thereof will be omitted. This embodiment differs from the previously described embodiments in that a gas exhaust pipe 31 is provided for exhausting the etching gas remaining in the gas introduction pipe 17.

That is, the gas exhaust pipe 31 is connected to the gas introduction pipe 17 at a position between the container 11 and the valve 16.

This gas exhaust pipe 31 is connected to a vacuum pump (not shown) that operates in synchronization with the high frequency power source 15. and,
At the same time as the high frequency power source 15 is turned off, the inside of the gas introduction pipe 17 is exhausted via the gas exhaust pipe 31. Further, in this example R, the gas introduction pipe 17 is connected within the container 11 to a manifold 32 for dispersing gas, so that the etching gas uniformly flows onto the sample 13.

With such a configuration, the gas in the gas introduction pipe 17 can be prevented from being introduced into the container 11 after etching is completed by the waste exhaust pipe 31, so that the same effect as in the previous embodiment can be obtained by 1q. Furthermore, since the manifold 32 is provided, the gas flowing onto the sample 13 can be made uniform, and the etching uniformity can be further improved. Here, the reason why the manifold 32 can be provided is as follows.
This is because the gas exhaust pipe 31 is provided. That is, due to the presence of the manifold 32, the manifold 32
However, in this embodiment, the gas exhaust pipe 31 prevents this from flowing into the container 11.

Note that the present invention is not limited to the embodiments described above. For example, uniform etching is possible if the opening/closing valve is provided at a position immediately before the point where the gas introduction pipe is connected to the container or within 10a from the point where the gas introduction pipe is connected to the container, and in this case, a position as close to the container as possible is preferable. Further, the on-off valve is not necessarily limited to an electromagnetic on-off valve, and various on-off valves can be used.

However, in order to operate in synchronization with a high-frequency power source, it is desirable to be able to control opening and closing electrically. In addition, as the etching gas activation means, for example (Proc
, of 4th 3ymp , onQry Pro
A light irradiation mechanism such as that disclosed in J. Chesses, 1982, p. 6) may also be used. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a conventional dry etching device, and Fig. 2 is a characteristic diagram for explaining the problems of the above device.
FIG. 3 is a schematic block diagram showing a dry etching apparatus according to an embodiment of the present invention, FIG. 4 is a characteristic diagram for explaining the operation of the apparatus of the above embodiment, and FIG. FIG. 3 is a diagram showing the configuration of main parts. 11... Etching container, 11a... Anode, 111
]...Gas inlet, 11c...Gas exhaust port, 12.
... Cathode, 13... Sample, 14... Matching circuit, 15... High frequency power supply, 16... Electromagnetic opening/closing valve,
17... Gas introduction pipe, 18... Switch circuit, 19
．． 31... Gas exhaust pipe, 32... Manifold. Applicant's agent Patent attorney Takehiko Suzue

Claims (8)

[Claims] (1) An etching container in which a sample to be etched is stored, a gas introduction pipe connected to the container and introducing an aluminum etching gas into the container, and means for activating the scum introduced into the container. and an opening/closing valve provided at or near a position immediately before the gas introduction pipe comes into contact with the container to open and close the gas flow path of the introduction pipe, and a waste exhaust means for exhausting the inside of the container. An aluminum dry etching device that is characterized by: (2) The aluminum tri-etching apparatus according to claim 1, wherein the on-off valve is an electromagnetic on-off valve. (3) The means for activating the scum consists of parallel plate type electrodes placed oppositely in the etching container and means for applying high frequency power between these electrodes.
An aluminum dry etching apparatus according to claim 1. (4) The aluminum dry etching apparatus according to claim 3, wherein the opening/closing valve closes at the same time as the high frequency power is turned off. (5) The aluminum dry etching apparatus according to claim 1, wherein the means for activating the gas is a light irradiation mechanism. (6) An etching container in which a sample to be etched is stored, a gas introduction pipe connected to this container and introducing gas for aluminum etching into the container, and activating the scum introduced into the container. means, an opening/closing valve provided at or near a position of the gas conduit tube in contact with the container and opening/closing the gas flow path of the introduction tube; a first gas exhaust means for exhausting the inside of the container; An aluminum dry etching apparatus comprising a second exhaust means for exhausting the inside of the gas introduction pipe between the opening/closing valve and the container. (7) The aluminum dry etching apparatus according to claim 6, wherein the on-off valve is an electromagnetic on-off valve. (8) Claim 6, characterized in that the means for activating the gas comprises parallel plate type electrodes arranged oppositely in the etching container, and means for applying high frequency power between these electrodes. Aluminum dry etching equipment as described in . ■ Said Iil! Claim 8, wherein the closing valve performs a closing operation at the same time as the high-frequency power is turned off, and the second exhaust means performs an exhaust operation at the same time as the high-frequency power is turned off. The aluminum dry etching apparatus described. 7. The aluminum dry etching apparatus according to claim 6, wherein the means for activating the lff+ gas is a light irradiation mechanism.